Under sponsorship of a series of SBIR Phase I & II programs, Nimbus and the University of Pittsburgh (UOP) have made significant progress in development of an implantable axial flow blood pump intended for chronic circulatory support. As a result, prototype designs of the pump, its cannulae, and a console based controller are nearing formal qualification testing. One element which remains to be developed is a portable, wearable controller. This controller frees the patient from being tethered to a console, and, from the users point of view it is a most critical element of the system. Indeed, successful, wide-spread application of the axial flow pump system will in large part depend upon the utility of this component. Considering its importance, and the scope of the task required to develop a portable, wearable controller, a separate Phase I effort is proposed. It involves the design, fabrication, and test evaluation of several innovative concepts. The goal is to demonstrate the feasibility of these concepts as determined by functional requirements being met, and its acceptance by simulated users. If these are accomplished successfully, the last vital element of the implantable axial flow blood pump system will have been defined in anticipation of animal trials. PROPOSED COMMERCIAL APPLICATION: An estimate of the potential market for chronic, implantable blood pump systems is 50,000 to 100,000 applications yearly, worldwide. A low cost, safe, and effective axial flow blood pump system would have the potential to capture a significant portion of those numbers. It is noted that each application would likely involve two or three portable controllers.